Incidence of cancer in the course of chronic pancreatitis.

Objective: Chronic pancreatitis patients appear to present an increased incidence of pancreatic cancer. The aim of the study was to compare the incidence of cancer, whether pancreatic or extrapancreatic, in our chronic pancreatitis cases with that in the population of our region.

Methods: We analyzed 715 cases of chronic pancreatitis with a median follow-up of 10 yr (7287 person-years); during this observation period they developed 61 neoplasms, 14 of which were pancreatic cancers. The cancer incidence rates were compared, after correction for age and gender, with those of a tumour registry.

Results: We documented a significant increase in incidence of both extrapancreatic (Standardized Incidence Ratio [SIR], 1.5; 95% confidence interval [CI], 1.1-2.0; p <0.003) and pancreatic cancer (SIR, 18.5; 95% CI, 10-30; p <0.0001) in chronic pancreatitis patients. Even when excluding from the analysis the four cases of pancreatic cancer that occurred within 4 yr of clinical onset of chronic pancreatitis, the SIR is 13.3 (95% CI, 6.4-24.5; p <0.0001). If we exclude these early-onset cancers, there would appear to be no increased risk of pancreatic cancer in nonsmokers, whereas in smokers this risk increases 15.6-fold.

Conclusions: The risks of pancreatic and nonpancreatic cancers are increased in the course of chronic pancreatitis, the former being significantly higher than the latter. The very high incidence of pancreatic cancer in smokers probably suggests that, in addition to cigarette smoking, some other factor linked to chronic inflammation of the pancreas may be responsible for the increased risk.